The present invention relates to a method for performing a percutaneous extraforaminotomy with foraminal ligament resection, which is capable of relieving pain by discharging an inflammatory material existing in spinal canal through intervertebral foramen to the outside, and instrument tools used for the same, and more particularly, to a percutaneous extraforaminotomy with foraminal ligament resection, which expands the size of intervertebral foramen by resecting minute ligaments entangled in the intervertebral foramen through instrument tools such that a chemical material supplied to spinal canal through a catheter and an inflammatory material existing in the spinal canal are smoothly discharged to the outside through the intervertebral foramen, and instrument tools used for the same.
As of now, various articles have provided an anatomical description of the transforaminal ligaments of the lumbar spine and many authors have conducted the radiological analysis of the transforaminal ligaments. Even if the authors discussed the possible clinical implications of these ligaments, it is unclear what clinical implications of these ligaments are. In particular, the influence of TFL (transforaminal ligament) has been insignificant to the surgeons who focus on the mechanical factors such as disc bulging, ligament thickening, facet hypertrophy, and structural changes like stenosis and spondylolisthesis.
On the other hand, it is quite reasonable to presume that any situation which diminishes the size of the intervertebral foramen, such as stenosis or loss of intervertebral disc height, would increase the relative amount of area in the foramen occupied by the transforaminal ligaments. However, the study and analysis regarding the clinical significance of this is presently not sufficient.
This article—Jun-Hong Min, et. al. “anatomic analysis of the transforaminal ligament in the lumbar intervertebral foramen” operative neurosurgery Vol. 57:37˜41, July 2005.—provides an anatomical description of the transforaminal ligaments of the lumbar spine. Although the importance of these structures is not yet clear, they may contribute to nerve root compression in certain cases. As such, they may contribute to persistent symptoms after more medical decompressive procedure. Spine surgeons should be aware of the presence of these structures and may consider them in the etiology of otherwise unexplained sciatic symptoms.
The article introduced above is an excellent and timely article in evaluating the anatomical analysis of the transforaminal ligaments of the lumbar intervertebral foramen, because the posterolateral approach is becoming more popular for the surgical treatment of lumbar far-lateral discs and foraminal stenosis.
Even if surgeons usually do not search for transforaminal ligaments during posterior foraminotomy, it is important and also useful for surgeons to have anatomical information in this area. It will be of great value and informative for neurosurgeons if the authors could conduct the radiological analysis of the transforaminal ligaments and study the correlation between anatomical and the surgical anatomy of the intervertebral foramen in the near future.
FIG. 1 is a view illustrating clinical anatomy of intervertebral foramen. The intervertebral foramen consists of spinal nerve (dorsal root ganglion), sinuvertebral nerves, veins (radicular vein, intervertebral veins), spinal artery, and ligaments.
FIG. 2 is a schematic diagram from the external aspect of intervertebral foramen. 1. Spinal artery, 2. Ventral ramus of spinal nerve, 3. Recurrent meningeal nerve, 4 and 5. Medial and lateral divisions of dorsal primary ramus, 6. Veins.
FIG. 3 is a view illustrating clinical anatomy of transforaminal ligament and FIG. 4 is a view illustrating a model image of lumbosacral spine.
As shown in FIG. 3, ligaments around the intervertebral foramen are categorized into four parts: ligaments of the entrance zone, ligaments of the mid-zone, ligaments of the exit zone, and ligaments of the post-canal zone. The ligaments of the entrance zone consist of posterior longitudinal ligament, Hoffmann ligament, and peridural membrane; the ligaments of the mid-zone include fascial condensations attaching the nerve root sleeve to the pedicles and ligamentum flavum; the ligaments of the exit zone (around intervertebral foramen) contain internal ligament, transforaminal ligament, and external ligament; and the ligament of the post-canal zone include lumbar cribriform fascia.
On the other hand, Amonoo-Kuofi et al. (1998a) J. Ant. 156, p 177˜183 divided TFLs (transforaminal ligaments) into three categories: internal ligaments, intraforaminal ligaments, and external ligaments. The internal ligament group includes the oblique inferior TFL (transforaminal ligament); the intraforaminal ligament group includes the deep anterior intraforaminal ligament, the oblique superior TFL (transforaminal ligament), and the horizontal mid-TFL (transforaminal ligament); and the external ligament group contains the superior, middle, and inferior corporotransverse ligaments. However, a different classification is applied to the L5, S1 IVF (intervertebral foramen), as shown in FIG. 4. The L5, S1 IVF (intervertebral foramen) consists of four types of ligamentous structure: the lumbosacral ligament, the lumbosacral hood, the corpotransverse ligament, and the mamillo-transverso-accessory ligament.
FIG. 5 is a view illustrating clinical anatomy of ligament closing intervertebral foramen, which is different for each patient. A. Oblique inferior TFL, B. Anterior intraforaminal ligament, C. Oblique superior TFL, D. Mid-TFL, E. Superior and inferior corporotransverse ligament, and F. Corporotransverse ligament.
Role of the foraminal ligament in the induction of low back pain including sciatica is divided into two aspects: inflammatory aspect and mechanical aspect. In terms of the inflammatory aspect, low back pain is affected by a series of processes such as activation of fine and non-myelinated pain endings, release of proinflammatory cytokines, vasodilation and edema, and adhesive fibrosis. In terms of the mechanical aspect, the below conditions should be considered: periradicular fibrosis, malposition of the transarticular ligament (especially, superior and inferior corporotransverse ligament) due to acquired reduction of intervertebral disc height, ossification of foraminal ligament, anomalies of trunks and conjoint nerve root, and entrapment of dorsal root ganglia (L5: corporotransverse ligament, L1-L4: inferior corporotransverse ligament).
Whereas the chemical neurolysis is applied to the problems of the inflammatory aspect, the mechanical epidural neurolysis by caudal catheterization or percutaneous extraforaminotomy is used to solve the problems of the mechanical aspect.
Back pain is a very common symptom that most of people experience more than once for the whole life. It is known that from 70 to 80 percent among the patients with back pain can be improved through the conservative method without a special treatment. The cases accompanying sciatica among the patients with back pain amount to about from 13 to 40 percent. Pathophysiological reason of sciatica is divided into mechanical factor and biochemical factor. In point of fact, we have neurosurgically put emphasis on mechanical factors such as disc bulging, ligament thickening, and facet hypertrophy for the treatment of sciatica. That is, most of neurosurgeons have believed that mechanical problems such as disc herniation and spinal stenosis cause sciatica, much more back pain.
However, with the introduction of epidural neurolysis, the inflammatory reaction around the intervertebral foramen has been considered as a main reason of sciatica.
FIG. 6 is a schematic view illustrating an image for explaining the process of pain and nerve dysfunction. The process of pain and nerve dysfunction may be easily understood with reference to FIG. 6.
Step A: Activation of adhesion molecules in the endoneurial capillary by tumor necrosis factor (TNF)
Step B: 1) Adhesion of circulating white blood cells (WBC), 2) Extravasation of WBC, and 3) Aggregation of thrombocytes and formation of a thrombus
Step C: 1) Local release of TNF, Myelin injury, Accumulation of Na-like channels, Induction of allodynia in dorsal root ganglion (DRG) and spinal cord, 2) Decreased blood flow and increased permeability nutritional deficit
In other words, biochemical factors undetected by magnetic resonance imaging (MRI) such as insufficient blood supply to nerve, mild inflammation, and fibroblastic adhesion around intervertebral foramen is in more important position.
So far, however, the surgery for treating pain of disc patients has relied on neurosurgical treatment for mechanical factors rather than analysis of biochemical factors which are not checked by MRI.